Confirmation to leave page is displayed if CKEditor is used

If CKEditor is used as default XWiki editor, after Add topic or Add answer button is pressed (content is already written in the editor), notification about if to leave the page (in Chorme "Do you want to leave this site?") is displayed. If the leave is confirmed, the topic or answer is correctly added to forum.

Tested in Windows 10 with Edge, Firefox and Chrome.